Couch Surfing
   Network connecting travelers with locals offering accommodations and advice. Members can be vouched for by other members or verified by paying a fee. Includes information about the organization, searchable database, message board, and chat room.
   http://www.couchsurfing.com

Friendship Force
   Nonprofit cultural exchange organization promoting friendship and goodwill through an extensive program of homestay exchanges since 1977.
   http://www.friendshipforce.org

Global Freeloaders
   Online community matching guests and hosts for accommodation exchange. Testimonials, FAQs, and a member database.
   http://www.globalfreeloaders.com

Hospitality Club
   Volunteer members offer free accommodation and travel help and leave comments in each others' profiles after the stay. Includes a forum, chat, and wiki travel guides.
   http://www.hospitalityclub.org

Hospitality Exchange
   Publishes a paper membership directory twice a year, there is a membership fee.
   http://www.hospex.net

International Police Association
   This organization includes a Hospitality Club for retired and active law enforcement officers.
   http://www.ipa-usa.org

Lesbian & Gay Hospitality Exchange International
   Network of lesbians and gay men from around the world who offer their hospitality to other members.
   http://www.lghei.org

MeetURplanet
   Australia-based club. Registration is free but paid membership is required to contact other members.
   http://www.meeturplanet.com

Pasporta Servo
   For people speaking Esperanto. There is a membership fee.
   http://www.tejo.org/ps/

Place2Stay
   Offers a worldwide network of private accommodations. Includes information about accommodations, a forum, FAQ and chat room.
   http://www.place2stay.net

Servas International
   Oldest hospitality exchange organization. Website includes a newsletter, FAQ and list of countries. There is a membership fee and new members are interviewed by Servas representatives.
   http://www.servas.org/

Teachers Travel Web
   Open to all educators. Site also includes home exchange listings.
   http://www.teacherstravelweb.com

Warm Showers List
   List of cyclists who offer their hospitality towards other touring cyclists.
   http://www.rogergravel.com/wsl/vh_for_a.html

Welcome Traveller Network
   Members pay a nominal fee for bed and breakfast when visiting other members. There are several interest groups.
   http://www.welcometraveller.org

Women Welcome Women World Wide
   For women only. Aims to foster international friendship by enabling women of different countries to visit one another. There is a membership fee.
   http://www.womenwelcomewomen.org.uk